diff --git a/Projects/AlPhaPha/2024/Calibration/VAMOS/CHIO/Chio_Z_Calibration.cal b/Projects/AlPhaPha/2024/Calibration/VAMOS/CHIO/Chio_Z_Calibration.cal
new file mode 100644
index 0000000000000000000000000000000000000000..88b652ee2bb38bd16544e3e8bfee9b22b7354796
--- /dev/null
+++ b/Projects/AlPhaPha/2024/Calibration/VAMOS/CHIO/Chio_Z_Calibration.cal
@@ -0,0 +1 @@
+IC_Z_CALIBRATION 84.055 -0.0196758 2.59494e-06 -1.50991e-10 4.36153e-15 -4.99792e-20
diff --git a/Projects/AlPhaPha/2024/macro/Calibration/IC/ReadMe.md b/Projects/AlPhaPha/2024/macro/Calibration/IC/ReadMe.md
index e1d082edac2010d9d4652fe6ace717e6e9ea1d97..12fd80c691be4e977900573264d31a72d0d12e24 100644
--- a/Projects/AlPhaPha/2024/macro/Calibration/IC/ReadMe.md
+++ b/Projects/AlPhaPha/2024/macro/Calibration/IC/ReadMe.md
@@ -41,7 +41,7 @@ those histograms.
 
 Those spline are the one used to flatten the distribution and are the calibration that we seek from this macro.
 
-**If you wan to improve the Z resolution** : The IC 2-3 are well behaved but the 4 has a factor 2 in the analysis.
+**If you want to improve the Z resolution** : The IC 2-3 are well behaved but the 4 has a factor 2 in the analysis.
 Therefore one should be very careful about the range in which the spline is made for IC4 !! 
 This is a point to be improved !
 
@@ -67,11 +67,11 @@ Name them CutZ CutZ0 CutZ02 CutZ023 CutZ0234, they correspond to different corre
 ```
 root 'DEYcorrection.C(true,true)'
 ```
-** TWO TIMES IN A ROW** 
+**TWO TIMES IN A ROW** 
 Then you should see all the histograms filled and beautiful.
 
 **Now rerun an analysis and the IC.DE and IC.Eres should give a good vamos plot**
-
+- You should uncomment the spline line in config/ConfigIC.dat
 
 # Step 4 : Cut Auto for Z id
 
@@ -104,4 +104,26 @@ This macro output the TCUTG in a root file in the output folder.
 
 # Step 5 : Flattening of the DE.
 
-Currently working on this.
+SplineChio.C make a spline for each cut generated in Step4 and modify each event according to it's distance to the two nearest
+spline. 
+
+The macro should be used as following :
+
+```
+root
+.L SplineChio.C
+
+SplineChio() # Only for first use after analysis
+
+MakeSpline() # Generate the spline and save them in the Calibration file
+
+ApplySpline() #Generate the calibration of each peak to get Z and save them in the Calibration dir
+```
+
+Don't forget to modify the configs/ConfigIC.dat with the proper token ! 
+- LOAD_Z_SPLINE ./Calibration/VAMOS/CHIO/Z_Spline.root
+- LOAD_Z_SPLINE_EVAL ./Calibration/VAMOS/CHIO/Chio_Z_Spline_Eval.txt
+
+When it's done and the graphs look alright rerun the analysis.
+
+Then you can fill and fit the histo using the associated macro to see the resolution in Z. :)